The MB-N10 battery pack extends autonomous operating time by approximately 1.8x and facilitates more comfortable balance when using long tele lenses. It is powered by up to two Nikon EN-EL15b rechargeable Li-ion batteries (available separately). The dust and moisture protected battery pack features a LED battery charge indicator for each of the two battery chambers. Hot swapping of batteries is supported, convenient for use with extended video shooting or interval timer photography. Direct charging of batteries installed in the battery grip is supported by using the AC charging adapter EH-7P (available separately). If the battery pack is attached to the camera, the camera needs to be turned off in order to activate battery charging via the grip’s integrated USB-port.